The invention relates to the use of amino-substituted hydroxybenzophenones as photostable UV filters in cosmetic and pharmaceutical preparations for protecting the human epidermis or human hair from UV radiation, specifically in the range from 320 to 400 nm.
The sunscreens employed in cosmetic and pharmaceutical preparations have the task of preventing, or at least diminishing the consequences of, harmful effects of sunlight on the human skin. However, these sunscreens also serve to protect other ingredients from decomposition or -breakdown by UV radiation. In hair cosmetic formulations the aim is to reduce damage to the keratin fibers by UV rays.
The sunlight reaching the surface of the earth contains proportions of UV-B radiation (280 to 320 nm) and UV-A radiation ( greater than 320 nm), which are directly adjacent to the visible light region. The effect on the human skin is manifested, particularly in the case of UV-B radiation, by sunburn. Accordingly, the industry offers a relatively large number of substances which absorb UV-B radiation and thus prevent sunburn.
Dermatological investigations have now shown that UV-A radiation is also perfectly capable of causing skin damage and allergies by, for example, damaging the keratin or elastin. This reduces the elasticity and water storage capacity of the skin, i.e. the skin becomes less supple and tends to form wrinkles. The noticeably high incidence of skin cancer in regions where the sun""s radiation is strong shows that damage to the genetic information in the cells is evidently also caused by sunlight, specifically by UV-A radiation. All these findings therefore make it appear necessary to develop efficient filter substances for the UV-A region.
There is a growing demand for sunscreens for cosmetic and pharmaceutical preparations which can be used in particular as UV-A filters and whose absorption maxima ought therefore to be in the range from about 320 to 380 nm. In order to achieve the required effect using the minimum amount, sunscreens of this type ought additionally to have a high specific absorbance. Sunscreens for cosmetic products must also meet a large number of other requirements, for example good solubility in cosmetic oils, high stability of the emulsions produced with them, toxicological acceptability, and low intrinsic odor and low intrinsic color.
Another requirement which sunscreens must meet is adequate photostability. However, this is only inadequately ensured, if at all, with the UV-A-absorbing sunscreens hitherto available.
French Patent No. 2 440 933 describes 4-(1,1-dimethylethyl)-4xe2x80x2-methoxydibenzoylmethane as a UV-A filter. It is proposed to combine this specific UV-A filter, which is sold by GIVAUDAN under the name xe2x80x9cPARSOL 1789xe2x80x9d, with various UV-B filters in order to absorb all UV rays having a wavelength from 280 to 380 nm.
However, this UV-A filter does not have sufficient photochemical stability, when used alone or in combination with UV-B filters, to ensure sustained protection of the skin during sunbathing for prolonged periods, which means that repeated applications at regular and short intervals are required if effective protection of the skin from all UV rays is desired.
For this reason, EP-A-0 514 491 discloses the stabilization of the insufficiently photostable UV-A filters by adding 2-cyano-3,3-diphenylacrylic esters which themselves act as filters in the UV-B region.
It has furthermore already been proposed in EP-A-0 251 398 and EP-A-0 416 837 to combine chromophores absorbing UV-A radiation and UV-B radiation into one molecule using a linker. This has the disadvantage that firstly a free combination of UV-A and UV-B filters in the cosmetic preparation is no longer possible, and that difficulties in the chemical linkage of the chromophores allow only certain combinations.
It is an object of the present invention to propose sunscreens for cosmetic and pharmaceutical purposes-which absorb in the UV-A region with high absorbance, which are photostable, have low intrinsic color, i.e. a sharp band structure, and are soluble in oil or water depending on the substituent.
We have found that this object is achieved by the use of amino-substituted hydroxybenzophenones of the formula I 
in which the variables independently of one another have the following meanings:
R1 and R2 are hydrogen, C1-C20-alkyl, C2-C10-alkenyl, C3-C10-cycloalkyl, C3-C10-cycloalkenyl, where the substituents R1 and R2 together with the nitrogen atom to which they are bonded can form a 5- or 6-membered ring;
R3 and R4 are C1-C20-alkyl, C2-C10-alkenyl, C3-C10-cycloalkyl, C3-C10-cycloalkenyl, C1-C12-alkoxy, C1-C20-alkoxycarbonyl, C1-C12-alkylamino, C1-C12-dialkylamino, aryl, heteroaryl, optionally substituted, substituents which confer solubility in water, chosen from the group consisting of a nitrile group, carboxylate, sulfonate or ammonium radicals;
x is hydrogen, COOR5, CONR6R7;
R5 to R7 are hydrogen, C1-C20-alkyl, C2-C10-alkenyl, C3-C10-cycloalkyl, C3-C10-cycloalkenyl, xe2x80x94(Yxe2x80x94O)oxe2x80x94Z, aryl;
Y is xe2x80x94(CH2)2xe2x80x94, xe2x80x94(CH2)3xe2x80x94, xe2x80x94(CH2)4xe2x80x94, xe2x80x94CH(CH3)xe2x80x94CH2xe2x80x94;
Z is xe2x80x94CH213 CH3, xe2x80x94CH213 CH213 CH3, xe2x80x94CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94CH3, xe2x80x94CH(CH3)xe2x80x94CH3;
m is from 0 to 3;
n is from 0 to 4;
o is from 1 to 20
as photostable UV filters in cosmetic and pharmaceutical preparations for protecting the human skin or human hair from the sun""s rays, alone or together with compounds which absorb in the UV region and are known per se for cosmetic and pharmaceutical preparations.
Alkyl radicals R1 to R7 which may be mentioned are branched or unbranched C1-C20-alkyl chains, preferably methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl or n-eicosyl.
Alkenyl radicals R1 to R7 which may be mentioned are branched or unbranched C2-C10-alkenyl chains, preferably vinyl, propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, 3-methyl-1-butenyl, 1-hexenyl, 2-hexenyl, 1-heptenyl, 2-heptenyl, 1-octenyl or 2-octenyl.
Cycloalkyl radicals which may be mentioned for R1 to R7 are preferably branched or unbranched C3-C10-cycloalkyl chains such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, 1-methylcyclopropyl, 1-ethylcyclopropyl, 1-propylcyclopropyl, 1-butylcyclopropyl, 1-pentylcyclopropyl, 1-methyl-1-butylcyclopropyl, 1,2-dimethylcyclopropyl, 1-methyl-2-ethylcyclopropyl, cyclooctyl, cyclononyl or cyclodecyl.
Cycloalkenyl radicals which may be mentioned for R1 to R7 are preferably branched or unbranched C3-C10-cycloalkenyl chains with one or more double bonds such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, cycloheptenyl, cycloheptatrienyl, cyclooctenyl, 1,5-cyclooctadienyl, cyclooctatetraenyl, cyclononenyl or cyclodecenyl.
The cycloalkenyl and cycloalkyl radicals may be unsubstituted or substituted by one or more, e.g. 1 to 3, radicals such as halogen, e.g. fluorine, chlorine or bromine, cyano, nitro, amino, C1-C4-alkylamino, C1-C4-dialkylamino, hydroxyl, C1-C4-alkyl, C1-C4-alkoxy or other radicals, or contain 1 to 3 heteroatoms such as sulfur, nitrogen, whose free valences can be saturated by hydrogen or C1-C4-alkyl, or oxygen in the ring.
Suitable alkoxy radicals for R3 and R4 are those having 1 to 12 carbon atoms, preferably having 1 to 8 carbon atoms.
Examples which may be mentioned are:
Examples of alkoxycarbonyl radicals for R3 and R4 are esters containing the abovementioned alkoxy radicals or radicals derived from higher alcohols, e.g. having up to 20 carbon atoms, such as iso-C15 alcohol.
Suitable mono- or dialkylamino radicals for R3 and R4 are those containing alkyl radicals having 1 to 12 carbon atoms, such as methyl, n-propyl, n-butyl, 2-methylpropyl, 1,1-dimethylpropyl, hexyl, heptyl, 2-ethylhexyl, isopropyl, 1-methylpropyl, n-pentyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-methyl-1-ethylpropyl and octyl.
Aryl means aromatic rings or ring systems having 6 to 18 carbon atoms in the ring system, for example phenyl or naphthyl, each of which may be unsubstituted or substituted by one or more radicals such as halogen, e.g. fluorine, chlorine or bromine, cyano, nitro, amino, C1-C4-alkylamino, C1-C4-dialkylamino, hydroxyl, C1-C4-alkyl, C1-C4-alkoxy or other radicals. Unsubstituted or substituted phenyl, methoxyphenyl and naphthyl are preferred.
Heteroaryl radicals are advantageously simple or fused aromatic ring systems having one or more heteroaromatic 3- to 7-membered rings. Heteroatoms which may be present in the ring or ring system are one or more nitrogen, sulfur and/or oxygen atoms. Hydrophilic radicals, i.e. those making it possible for the compounds of the formula I to dissolve in water, for R3 and R4 are, for example, the nitrile group and carboxyl and sulfoxy radicals and, in particular, their salts with any physiologically tolerated cations, such as the alkali metal salts or such as the trialkylammonium salts, such as tri(hydroxyalkyl)ammonium salts or the 2-methyl-1-propanol-2-ammonium salts. Also suitable are ammonium radicals, especially alkylammonium radicals, with any physiologically tolerated anions.
The substituents R1 and R2 can, together with the nitrogen atom to which they are bonded, form a 5- or 6-membered ring, for example a pyrrolidine or piperidine ring.
The amino group can be in the ortho, meta or para position relative to the carbonyl group. The para position is preferred.
Preference is given to compounds of the formula Ib 
in which the substituents independently of one another have the following meanings:
R1 and R2 are hydrogen, C1-C12-alkyl, where the substituents R1 and R2 together with the nitrogen atom to which they are bonded can form a 5- or 6-membered ring;
R5 is hydrogen, C1-C12-alkyl, C3-C6-cycloalkyl.
Alkyl radicals for R1, R2 and R5 which may be mentioned are branched or unbranched C1-C12-alkyl chains, preferably methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl or 2-ethylhexyl.
Particularly preferred alkyl radicals for R1, R2 and R5 which may be mentioned are methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 2-ethylhexyl.
Particularly preferred C3-C6-cycloalkyl radicals for R5 which may be mentioned are cyclopropyl, cyclopentyl and cyclohexyl.
Furthermore, compounds of the formula Ib in which the substituents R1, R2 and R5 are present in the combination given in Table 1 have particular photostable properties:
The compounds given in Table I have a photostability of  greater than 95%, preferably  greater than 98%.
The invention also relates to amino-substituted hydroxybenzophenones of the formula Ic, 
in which the variables independently of one another have the following meanings:
R1 and R2 are hydrogen, C1-C8-alkyl, where the substituents R1 and R2 together with the nitrogen atom to which they are bonded can form a 5- or 6-membered ring;
X is COOR5, CONR6R7;
R5 is C2-C12-alkyl, C5-C6-cycloalkyl;
R6 and R7 are hydrogen; C1-C12-alkyl, C5-C6-cycloalkyl.
Alkyl radicals R1 and R2 which may be mentioned are branched or unbranched C1-C8-alkyl chains, preferably methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl or 2-ethylhexyl.
Alkyl radicals R5 which may be mentioned are branched or unbranched C2-C12-alkyl chains, preferably ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl-, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.
Alkyl radicals R6 and R7 which may be mentioned are branched or unbranched C1-C12-alkyl chains, preferably methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl or 2-ethylhexyl.
Cycloalkyl radicals which may be mentioned for R5 to R7 are, preferably, branched or unbranched C5-C6-cycloalkyl chains, such as cyclopentyl or cyclohexyl.
Preference is given to compounds of the formula Ic, in which independently of one another R1 and R2 are C1-C4-alkyl, R5 is C3-C8-alkyl, and R6 and R7 are C1-C8-alkyl.
Particular preference is given to compounds of the formula Ic in which independently of one another R1 and R2 are ethyl, R5 is C5-C8-alkyl, and R6 and R7 are C114 C8-alkyl from the listings of the substituents, given above, in each case.
The compounds of the formula I to be used according to the invention can be prepared by direct acylation of the corresponding amino-substituted phenols.
Thus, for example, the synthesis of methyl 2-(4-dimethylamino-2-hydroxybenzoyl)benzoate (1) or methyl 2-(2-hydroxy-4-pyrrolidin-1-ylbenzoyl)benzoate (2) can be carried out by acylation of meta-diethylaminophenol or 3-pyrrolidin-1-ylphenol respectively with phthalic anhydride, and subsequent esterification. 
In addition, (4-diethylamino-2-hydroxylbenzoyl)phenylmethanone (3) can, for example, be prepared by reaction of meta-diethylaminophenol with benzoyl chloride and subsequent Fries rearrangement with AlCl3. 
Details on the Friedel-Crafts reaction and on Fries""s rearrangement can be found in Organikum, VEB Deutscher Verlag der Wissenschaften, Berlin, 1986, pp. 323-327, and in Houben-Weyl, Vol. 7/2a, 1973, pp. 379-389.
The present invention also relates to cosmetic and pharmaceutical preparations which comprise from 0.1 to 10% by weight, preferably 1 to 7% by weight, based on the total amount of the cosmetic and pharmaceutical preparation, of one or more of the compounds of the formula I together with compounds which absorb in the UV-A and UV-B regions and are known per se for cosmetic and pharmaceutical preparations as sunscreens, where the compounds of the formula I are generally employed in a smaller amount than the UV-B-absorbing compounds.
The sunscreen-containing cosmetic and pharmaceutical preparations are, as a rule, based on a carrier which comprises at least one oil phase. However, preparations with an exclusively aqueous basis are also possible if compounds having hydrophilic substituents are used. Accordingly, oils, oil-in-water and water-in-oil emulsions, creams and pastes, protective lipstick compositions or fat-free gels are suitable.
Suitable emulsions are inter alia also O/W macroemulsions, O/W microemulsions or O/W/O emulsions containing amino-substituted hydroxybenzophenones of the formula I in dispersed form, the emulsions being obtainable by phase inversion technology, as in DE-A-197 26 121.
Conventional cosmetic ancillary substances which may be suitable as additives are, for example, coemulsifiers, fats and waxes, stabilizers, thickeners, biogenic active substances, film formers, fragrances, dyes, pearlizing agents, preservatives, pigments, electrolytes (e.g. magnesium sulfate) and pH regulators. Suitable and preferred coemulsifiers are known W/O as well as O/W emulsifiers such as polyglycerol esters, sorbitan esters or partially esterified glycerides. Typical examples of fats are glycerides; waxes which may be mentioned are, inter alia, beeswax, paraffin wax or microwaxes, possibly combined with hydrophilic waxes. Stabilizers which can be employed are metal salts of fatty acids such as, for example, magnesium, aluminum and/or zinc stearate. Examples of suitable thickeners are crosslinked polyacrylic acids and their derivatives, polysaccharides, in particular xanthan gum, guar-guar, agar-agar, alginates and tyloses, carboxymethylcellulose and hydroxyethylcellulose, also fatty alcohols, monoglycerides and fatty acids, polyacrylates, polyvinyl alcohol and polyvinylpyrrolidone. Examples of biogenic active substances are plant extracts, protein hydrolysates and vitamin complexes. Examples of film formers which are in use are hydrocolloids such as chitosan, microcrystalline chitosan or quaternized chitosan, polyvinylpyrrolidone, vinylpyrrolidone/vinyl acetate copolymers, polymers of the acrylic acid series, quaternary cellulose derivatives and similar compounds. Examples of suitable preservatives are formaldehyde solution, p-hydroxybenzoate or sorbic acid. Examples of suitable pearlizing agents are glycol distearic esters such as ethylene glycol distearate, but also fatty acids and fatty acid monoglycol esters. Dyes which can be used are the substances suitable and approved for cosmetic purposes, as tabulated, for example, in the publication xe2x80x9cKosmetische Fxc3xa4rbemittelxe2x80x9d of the Farbstoffkommission der Deutschen Forschungsgemeinschaft, published by Verlag Chemie, Weinheim, 1984. These dyes are normally employed in a concentration of from 0.001 to 0.1% of the total weight of the mixture.
An additional content of antioxidants is generally preferred. Thus, it is possible to use as favorable antioxidants all antioxidants which are customary or suitable for cosmetic and/or dermatological applications.
The antioxidants are advantageously chosen from the group consisting of amino acids (e.g. glycine, histidine, tyrosine, tryptophan) and derivatives thereof, imidazoles (e.g. urocanic acid) and derivatives thereof, peptides such as D,L-carnosine, D-carnosine, L-carnosine and derivatives thereof (e.g. anserine), carotenoids, carotenes (e.g. xcex2-carotene, lycopene) and derivatives thereof, chlorogenic acid and derivatives thereof, lipoic acid and derivatives thereof (e.g. dihydrolipoic acid), aurothioglucose, propylthiouracil and other thiols (e.g. thiorodoxin, glutathione, cysteine, cystine, cystamine and the glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl, and lauryl, palmitoyl, oleyl, xcex3-linoleyl, cholesteryl and glyceryl esters thereof) and salts thereof, dilauryl thiodipropionate, distearyl thiodipropionate, thiodipropionic acid and derivatives thereof (esters, ethers, peptides, lipids, nucleotides, nucleosides and salts), and sulfoximine compounds (e.g. buthionine sulfoximines, homocysteine sulfoximines, buthionine sulfones, penta-, hexa-, heptathionine sulfoximine) in very low tolerated doses (e.g. pmol to xcexcmol/kg), and also (metal)chelating agents (e.g. xcex1-hydroxy fatty acids, palmitic acid, phytic acid, lactoferrin), xcex1-hydroxy acids (e.g. citric acid, lactic acid, malic acid), humic acid, bile acid, bile extracts, bilirubin, biliverdin, EDTA and derivatives thereof, unsaturated fatty acids and derivatives thereof (e.g. xcex3-linolenic acid, linoleic acid, oleic acid), folic acid and derivatives thereof, ubiquinone and ubiquinol and derivatives thereof, vitamin C and derivatives thereof (e.g. ascorbyl palmitate, Mg ascorbylphosphate, ascorbylacetate), tocopherol and derivatives (e.g. vitamin E acetate, tocotrienol), vitamin A and derivatives (vitamin A palmitate), and coniferyl benzoate of benzoin resin, rutinic acid and derivatives thereof, xcex1-glycosylrutin, ferulic acid, fufurylideneglucitol, carnosine, butylhydroxytoluene, butylhydroxyanisole, nordihydroguaiac acid, nordihydroguaiaretic acid, trihydroxybutyrophenone, ureic acid and derivatives thereof, mannose and derivatives thereof, zinc and derivatives thereof (e.g. ZnO, ZnSO4), selenium and derivatives thereof (e.g. selenomethionine), stilbenes and derivatives thereof (e.g. stilbene oxide, trans-stilbene oxide).
The amount of the abovementioned antioxidants (one or more compounds) in the preparations is preferably from 0.001 to 30% by weight, particularly preferably from 0.05 to 20% by weight, in particular from 1 to 10% by weight, based on the total weight of the preparation.
If vitamin E and/or derivatives thereof are used as the antioxidant(s), it is advantageous to choose their particular concentration from the range from 0.001 to 10% by weight, based on the total weight of the formulation.
If vitamin A and/or derivatives thereof, or carotenoids are the antioxidant(s), it is advantageous to use their particular concentration from the range from 0.001 to 10% by weight, based on the total weight of the formulation.
Customary oil components in cosmetics are, for example, paraffin oil, glyceryl stearate, isopropyl myristate, diisopropyl adipate, cetylstearyl 2-ethylhexanoate, hydrogenated polyisobutene, vaseline, caprylic/capric triglycerides, microcrystalline wax, lanolin and stearic acid.
The total amount of auxiliaries and additives can be from 1 to 80% by weight, preferably from 6 to 40% by weight, and the nonaqueous content (xe2x80x9cactive substancexe2x80x9d) can be from 20 to 80% by weight, preferably from 30 to 70% by weight, based on the compositions. The compositions can be prepared in a manner known per se, i.e. for example by hot, cold, hot-hot/cold or PIT emulsification. This is a purely mechanical process; no chemical reaction takes place.
Such sunscreen preparations can accordingly be in liquid, paste or solid form, for example as water-in-oil creams, oil-in-water creams and lotions, aerosol foam creams, gels, oils, marking pencils, powders, sprays or alcoholic-aqueous lotions.
Finally, it is also possible to use other substances which absorb in the UV region and are known per se as long as they are stable in the overall system of the combination of UV filters to be used according to the invention.
Most of the sunscreens in the cosmetic and pharmaceutical preparations used for protecting the human epidermis consist of compounds which absorb UV light in the UV-B region, i.e. in the range from 280 to 320 nm. The content of UV-A absorbers to be used according to the invention is, for example, from 10 to 90%, by weight, preferably 20 to 50% by weight, based on the total 45 amount of UV-B- and UV-A-absorbing substances.
Any V-A and UV-B filter substances are suitable as UV filter substances which are used in combination with the compounds of the formula I to be used according to the invention. Examples which may be mentioned are:
The cosmetic and dermatological preparations according to the invention can advantageously further comprise inorganic pigments based on metal oxides and/or other metal compounds which are insoluble or virtually insoluble in water, in particular the oxides of titanium (TiO2), zinc (ZnO), iron (e.g. Fe2O3), zirconium (ZrO2), silicon (SiO2), manganese (e.g. MnO), aluminum (Al2O3), cerium (e.g. Ce2O3), mixed oxides of the corresponding metals, and admixtures of such oxides. Particular preference is given to pigments based on TiO2 and ZnO.
For the purposes of the present invention, it is particularly advantageous, but not obligatory, for the inorganic pigments to be present in hydrophobic form, i.e. to have been treated on the surface to repel water. This surface treatment can involve providing the pigments with a thin hydrophobic layer in a manner known per se, as described in DE-A-33 14 742.
To protect human hair against UV rays, the light protection agents of the formula I according to the invention can be incorporated into shampoos, lotions, gels, hairsprays, aerosol foam creams or emulsions in concentrations of from 0.1 to 10% by weight, preferably from 1 to 7% by weight. The respective formulations can be used, inter alia, for washing, coloring and for styling the hair.
The compounds to be used according to the invention are generally notable for particularly high absorbency in the region of UV-A radiation with a sharp band structure. Furthermore, they are readily soluble in cosmetic oils and can be readily incorporated into cosmetic formulations. The emulsions prepared with the compounds I are notable in particular for their high stability, the compounds I themselves for their high photostability, and the preparations prepared with I for their pleasant feel on the skin.
The UV filter action of the compounds according to the invention of the formula I can also be utilized for stabilizing active ingredients and auxiliaries in cosmetic and pharmaceutical formulations.
The examples below illustrate the preparation and use of the amino-substituted hydroxybenzophenones in more detail.